Asymmetry of the PLANCK antenna beam shape and its manifestation in the CMB data

¹ Theoretical Astrophysics Center, Juliane Maries Vej 30, 2100 Copenhagen, Denmark
² Niels Bohr Institute, Blegdamsvej 17, 2100 Copenhagen, Denmark
³ Astronomical Observatory, Juliane Maries Vej 30, 2100 Copenhagen, Denmark
⁴ Rostov State University, Zorge 5, 344090 Rostov-Don, Russia
⁵ Astronomy Department, University of Oxford, NAPL, Keble Road, Oxford OX1 3RH, UK
⁶ Astro-Space Center of Lebedev Physical Institute, Profsoyuznaya 84/32, Moscow, Russia
⁷ NORDITA, Blegdamsvej 17, 2100 Copenhagen, Denmark

Received: 9 October 2001
Accepted: 27 May 2002

Abstract

We present a new method to extract the beam shape incorporated in the pixelized map of CMB experiments. This method is based on the interplay of the amplitudes and phases of the signal and instrumental noise. By adding controlled white noise onto the map, the phases are perturbed in such a way that the beam shape manifests itself through the mean-squared value of the difference between original and perturbed phases. This method is useful in extracting preliminary antenna beam shape without time-consuming spherical harmonic computations.